This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our goal is to determine intermolecular interactions that regulate the concerted assembly of Venezuelan equine encephalitis virus (VEEV), an alphavirus that causes epidemics in the Central and South America, and a highly developed biological weapons agent without effective therapy. Aim 1. To determine interactions between the VEE virus capsid protein and RNA that promote viral nucleocapsid assembly, using complementary biochemical, biophysical, molecular and structural biology approaches. Aim 2. To determine if intermolecular capsid protein interactions within the nucleocapsid undergo large-scale rearrangements during VEE virus maturation by determining the structure of pre-viral, viral, and post-viral nucleocapsids.